At 5:04 PM +0200 2003/08/28, Peter J. Holzer wrote:
Still, I don't think there are many legitimate sites which don't have an
A record. Requiring the sender to send a FQDN which resolves to the
sender's IP address doesn't seem unreasonable to me (even for dynamic
IP-Addresses, you can use dyndns.net or a similar service).
Check the recent traffic on NANOG. Because of stupidity on the
part of AOL, they've been discussing this subject intensively. I've
been tagging 75-90% of the recent messages as input for the BCP
review.
In short, let me say that I used to think this was a good idea,
but my views are in the process of changing. Maybe we could tag and
score on the basis of whether or not the sender's IP address has
proper reverse DNS (or whether the sender's domain name exists in the
DNS and/or in some sense "matches" the IP address of the incoming
connection), but I think it would be foolish in the extreme to
outright reject messages on this basis.
In fact,
looking at my log files this seems to be a very good indicator of
legitimate mail servers (I checked several weeks of logs some time ago
and only found one legimitate server which identified itself with an
unresolvable name (I think the box is NATted).
I'm NAT'ed. Many people on NANOG appear to be in similar
situations, or have run into them frequently.
Just because we haven't personally experienced a particular
situation doesn't mean that this would necessarily make itself a good
target for filtering and outright rejection.
--
Brad Knowles, <brad(_dot_)knowles(_at_)skynet(_dot_)be>
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
-Benjamin Franklin, Historical Review of Pennsylvania.
GCS/IT d+(-) s:+(++)>: a C++(+++)$ UMBSHI++++$ P+>++ L+ !E-(---) W+++(--) N+
!w--- O- M++ V PS++(+++) PE- Y+(++) PGP>+++ t+(+++) 5++(+++) X++(+++) R+(+++)
tv+(+++) b+(++++) DI+(++++) D+(++) G+(++++) e++>++++ h--- r---(+++)* z(+++)
_______________________________________________
Asrg mailing list
Asrg(_at_)ietf(_dot_)org
https://www1.ietf.org/mailman/listinfo/asrg